ORGANICALLY BOUND TRITIUM IN WHEAT AFTER SHORT-TERM EXPOSURE TO ATMOSPHERIC TRITIUM UNDER LABORATORY CONDITIONS

The uptake, loss, conversion and translocation of tritium in wheat pla nts were determined following a unique short-time exposure to atmosphe ric tritium under laboratory conditions. Potted plants were exposed be tween anthesis and maturity, under day-time conditions at two differen t light intensities and during night conditions. Two data sets with ex posure conditions and corresponding tritium concentrations in plants a re given for rise in appropriate models. In leaves, the tritium uptake into tissue water was about four times lower under night conditions t han under day conditions, The initial relative concentrations of organ ically bound tritium in leaves observed under night conditions were ab out 50% of those observed under clay conditions, Translocation of orga nically bound tritium to grain was found to depend on rite growth rate of the grain. Once translocation to grain has taken place, organicall y bound tritium is lost only slowly. (C) 1997 Elsevier Science Limited .